One of the major techniques for determining the prognosis of cancer, particularly breast cancer, involves examining the lymph nodes of the axilla or armpit of the patient. It is well known that a major aspect in assessing the stage of the cancer revolves around whether the cancer has spread to the lymph nodes. It is therefore important to have an effective technique for identifying the spread of the cancer through the lymphatic system.
In the lymphatic system of the human body, lymphatic fluid flows from the breast through the lymph channels and is filtered through the lymph nodes. The first stop is the “first lymph node” or the “sentinel lymph node.” If the cancer has spread to the lymph nodes, the sentinel lymph node should be positive (i.e., cancerous). If the first lymph node is negative, it can be assumed that the rest of the lymph nodes are negative. Therefore, it is crucial that this first lymph node or sentinel lymph node be accurately identified.
A known technique for identifying the sentinel lymph node(s) involves the use of two substances: a blue substance and a radioactive substance. However, the sentinel lymph node may not be blue, or may not be radioactive, using this technique. This causes problems relating to the accuracy of the identification. Therefore, there is a need for an improved and more accurate technique for the identification of the sentinel lymph node.
In more detail, the known technique involves the two substances lymphazurin blue and sulfur colloid. There is a disadvantage to lymphazurin blue in that it cannot be radio-labeled. Another problem is that not only does the procedure require two substances, it also requires two separate injections. Therefore, there is a need for an improved and simplified technique for the identification of the sentinel lymph node.
Giuliano et al. describe the feasibility and accuracy of lymphatic mapping with sentinel lymphadenectomy in patients with breast cancer. (1) The conclusion was that lymphatic mapping can accurately identify the sentinel node in most patients.
Krag et al. describe the surgical resection and radiolocalization of the sentinel lymph node in breast cancer using a gamma probe. (2) It was concluded that radiolocalization and selective resection of sentinel lymph nodes is possible, and that the sentinel lymph node appears to predict correctly the status of the remaining axilla.
Wong describes a chemical method for labeling a hematoporphyrin derivative (HPD) with Technetium-99m. (3)
Rousseau et al. describe the synthesis, tissue distribution, and tumor uptake of 99Tc-labeled-tetrasulfophtalocyanine [99Tc] TSPC, which was prepared by condensing sulfophthalic acid and pertechnetate in the presence of a reducing agent. (4) Reaction products were purified in various chromatographic systems and were characterized by combustion, specific activity, and spectral analyses. 99Tc emits β radiation. TSPC is a tetrasulfonic acid derivative within a general class of compound known as phthalocyanines. Phthalocyanines are not naturally occurring substances, but they have been reported to mimic the activities of naturally occurring porphyrins. The tissue distribution pattern of the product was studied in rats bearing tumors. Most of the [99Tc] TSPC accumulated in the liver, kidneys, ovaries, and uterus, whereas tumor uptake occurred mainly in the exterior cell layers. The in vivo stability of the complex was evidenced by the absence of 99Tc accumulation in the thyroid and the stomach.
Weber et al. describe magnetic properties of transition metal derivatives of 4′,4″,4′″-Tetrasulfophthalocyanine. (5) The tetrasulfophthalocyanine complexes of manganese, iron, cobalt, nickel, and copper were prepared in high purity and the magnetic moments of these substances were determined both in the solid state and in solution.